Colombian police say the murder rate in the South American nation has fallen to its lowest level in two decades.

Police chief Gen Jorge Daniel Castro said that a total of 17,206 people suffered violent deaths in 2006, 517 fewer than in 2005.

Kidnappings also fell from 329 in 2005 to 200 in 2006, he said.

Colombia continues to have one of the highest murder rates in the world, but observers say security has been gradually improving in recent years.

The president, Alvaro Uribe, has worked to tackle violence linked to both right-wing paramilitary and left-wing rebel groups, and to the illegal drugs trade.

Gen Castro said the drop in the crime figures meant that progress was being made.

"This shows that we are going in a good direction, but we must do more to reduce these statistics," he said.

But as the figures were released, local officials said that left-wing Farc rebels shot four civilians, including two community leaders, at a remote village some 320 km (200 miles) north of Bogota on Monday.

"A group of insurgents, apparently from the 36 Front of the Farc, appeared and proceeded to massacre four people," Jose Jair Jimenez of the state governor's office told Reuters news agency.